The Shkval is a high-speed, supercavitating, rocket-propelled torpedo developed by Russia. It was designed to be a rapid-reaction defense against U.S. submarines undetected by sonar. It can also be used as a countermeasure to an incoming torpedo, forcing the hostile projectile to abruptly change course and possibly break its guidance wires.
The solid-rocket propelled torpedo achieves a high velocity of 250 knots (288 mph) by producing an envelope of supercavitating bubbles from its nose and skin, which coat the entire weapon surface in a thin layer of gas. This causes the metal skin of the weapon to avoid contact with the water, significantly reducing drag and friction.
The Shkval is fired from the standard 533-mm torpedo tube at a depth of up to 328 ft (100 m). The rocket-powered torpedo exits the tube at 50 knots (93 kmh) and then ignites the rocket motor, propelling the weapon to speeds four to five times faster than other conventional torpedoes. The weapon reportedly has an 80 percent kill probability at a range of 7,655 yd (7,000 m).
The torpedo is guided by an autopilot rather than by a homing head as on most torpedoes. Reportedly, there is a homing version of the Shkval that starts at the higher speed but slows and enters a search mode.
Notwithstanding its defense-motivated origins, the Shkval is potentially a very significant offensive threat. To date, no deck-launched anti-torpedo has been able to fulfill all of the above-mentioned requirements.